— 8i — 



Hab. : On rocks a little below the high tide-mark, often growing 

 together with Hydroclalhnts ccmccllatus、 &c. Nagasaki ； Provs. 

 Totomi, Surur^a, Boshyu and Noto ； Hakodate. 



Remarks : In our plants a frond bearing?- 9-anietangia sometimes 

 ripens sporangia in the same body, as it is showa in Fig'. 6. 



I have been fortunate enough to study the development of this 

 plant from zoospores. Though I was not able to follow every stag'e 

 of its development by cult 11 ring" one and the same material, it succeed- 

 'ed with me to study different materials at clifterent times to learn the 

 formation of a very younp' ironcl from the confervoicl prctonema-like 

 filaments, as it is illustrated in Figs. 9-14. 



PL. XVIII, Fips. 1-14. n?*. 1-2: Lcathcsia difforuiis in nat. 

 state and size. — riij. 3 : portion of the raaial lono-itudinal section of 

 frond ； f、 assimilatory filaments; h、 hair ； s、 ^ametangia ； さリ. 一 Fig". 

 4- ： root-fibres, ^ さ o. ― Fic?s. 5-8: p^ametangia and sporancjia ； f、 as- 

 similatory filaments ； s, o-ametangia ； ぶ，， the same emptied ； ど、 

 sporangia ； no-s. 5-6, 6 ミ 0; Figs. 7-8, ^ ミ 。• 



np^s. 914 ： different stap'es of development from zoospores, 

 tig. 9 ci- に. 6th, June, 1903, ^^o; "， zoospore, 3x5 /j. ； b、 zoospore 

 just settled, 5 tJ- in diam.; c、 spore just germinated; d、 a little ad- 

 vanced, 16 〃 long" ； c, one joint formed, 28 "- long. — Fie. 10 ct-k : alj 

 different materials ； a, 19 〃 Ion sy (i 2th, July, 1904) ； l\ 33 〃 ( 1 2th) ; c、 

 41 (13th) ； d、 55 X 5 ！,. (1 4th); e, 66x5 〃 (15th) ； f、 66 ド (15th) ； 

 55 〃 (15th) ； //， 96 "- (15th) ； /， 96 ！ 上 (i6th) ； j、 146 /X (1 6th) ； k、 lyj ft 

 (i 8th) ； 二;〜 一 Fk's. il a~c : ditierent stages of the same material; a、 ca. 

 330 « long (21th, July, 1904) ； b、 ca. 374 (23th) ; r, ca. 462 〃 （26th) ; 

 ^【5. ― rig. 12 : very young frond just fromed from the protonema-like 

 confervoicl filaments, seen from the under surface, May, 1903 ； g^o. ― 

 Fig. 13 : young' frond a little advanced, the inner tissue still dense and 

 compact, (May, 1903) ； や • 一 Fig- 14 ： same still advanced, the inner 

 tissue already hollowed up, (May. 1903) ； \. 



